The invention relates to a device for the power-assisted actuation of a tape-sensing lever in a magnetic-tape apparatus during switching from the playing mode of the apparatus to the reverse search mode of the apparatus, and more particularly to such an apparatus which which apparatus comprises only one drive motor for driving the two reel discs, which are driven through a centrally arranged pivotal drive mechanism. The direction of tape transport is reversed by reversing the direction of rotation of the drive motor, thus pivoting a lever carrying a coupling gear and a driving gear.
Magnetic-tape apparatuses for recording and reproduction are known in which some apparatus functions are controlled by changing the direction of rotation of the drive motor. For example, DE-PS No. 828,923 and DE-GM No. 1,730,790 disclose a device for controlling an audio-tape apparatus in which rewinding of the sound-carrier tape is controlled by changing the direction of rotation of the drive motor. In these known constructions an intermediate gear is pivoted about the shaft of the drive motor to mesh with either the take-up reel or with the supply reel depending on the direction of rotation of the motor. For this purpose the intermediate gear is preferably mounted on a pivotal lever which is supported on and pivots about the motor shaft. The intermediate gear wheel is, in mesh with a pinion which is rigidly mounted on the motor shaft. To provide pivoting torque, the pivotal level and the pinion on the motor shaft are in frictional engagement with one another. In a known modified device the intermediate gear, which is arranged on a pivotal lever in a similar way, follows a stationary roller path on the apparatus during the pivotal movement. This enables an apparatus function requiring much power to be carried out. An apparatus function requiring much power is, for example, disabling of the tape-tension control which was necessary during the playing mode of the apparatus, when switching from this playing mode to the reverse search mode of the apparatus. By means of a pivotal drive mechanism the direction of rotation of the reels is reversed substantially without any additional expenditure of power by reversing the direction of rotation of the drive motor. However, if at the same time as this rotation is reversed a spring-loaded tape-sensing lever is to be actuated, this briefly demands additional power. In the known device power conversion is effected by means of an intricate control profile formed on the pivotal lever. This has the disadvantage that the drive mechanism may become blocked inadvertently as a result of the free interengagement of the parts of the mechanism.